The EU has deliberately targeted products from states crucial to George Bush's upcoming presidential campaign.

A spokeswoman for the EU trade commissioner said it was not trying to "punish" the US, but to "focus the minds of the US administration".

Most affected goods will face additional tariffs of 30 per cent, some will be set at eight or 15 per cent, others at 100 per cent.

America's decision to impose the steel tariffs, due to run until 2005, have angered US-based car manufacturers. They claim the duties have increased the cost of their raw materials and caused job losses.

If the US refuses to back down, the sanctions will be the biggest in the history of the WTO.

Senior Republicans have conceded that it is time for the tariffs to go. But last night the White House spokesman Scott McClellan said: "We disagree with the overall WTO report. We are going to study it, look at its implications and go from there."

In July, a panel of two WTO judges found that Washington had failed to prove that its homegrown industry was under threat from steel imports. And yesterday's judgment by the organisation's highest trade court, the Appellate Body, upheld this finding.

The steel row is only one of several trade disputes between the EU and US. The EU has threatened sanctions next spring if tax breaks for American exporters continue. And the WTO is considering a US complaint that Europe blocks genetically modified imports.